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<div class="titlepage"><div><div><h3 class="title">
<a name="boost_asio.tutorial.tutdaytime2"></a><a class="link" href="tutdaytime2.html" title="Daytime.2 - A synchronous TCP daytime server">Daytime.2 - A synchronous
      TCP daytime server</a>
</h3></div></div></div>
<p>
        This tutorial program shows how to use asio to implement a server application
        with TCP.
      </p>
<pre class="programlisting">#include &lt;ctime&gt;
#include &lt;iostream&gt;
#include &lt;string&gt;
#include &lt;boost/asio.hpp&gt;

using boost::asio::ip::tcp;
</pre>
<p>
        We define the function <code class="computeroutput">make_daytime_string()</code> to create the string
        to be sent back to the client. This function will be reused in all of our
        daytime server applications.
      </p>
<pre class="programlisting">std::string make_daytime_string()
{
  using namespace std; // For time_t, time and ctime;
  time_t now = time(0);
  return ctime(&amp;now);
}

int main()
{
  try
  {
    boost::asio::io_context io_context;
</pre>
<p>
        A <a class="link" href="../reference/ip__tcp/acceptor.html" title="ip::tcp::acceptor">ip::tcp::acceptor</a>
        object needs to be created to listen for new connections. It is initialised
        to listen on TCP port 13, for IP version 4.
      </p>
<pre class="programlisting">    tcp::acceptor acceptor(io_context, tcp::endpoint(tcp::v4(), 13));
</pre>
<p>
        This is an iterative server, which means that it will handle one connection
        at a time. Create a socket that will represent the connection to the client,
        and then wait for a connection.
      </p>
<pre class="programlisting">    for (;;)
    {
      tcp::socket socket(io_context);
      acceptor.accept(socket);
</pre>
<p>
        A client is accessing our service. Determine the current time and transfer
        this information to the client.
      </p>
<pre class="programlisting">      std::string message = make_daytime_string();

      boost::system::error_code ignored_error;
      boost::asio::write(socket, boost::asio::buffer(message), ignored_error);
    }
  }
</pre>
<p>
        Finally, handle any exceptions.
      </p>
<pre class="programlisting">  catch (std::exception&amp; e)
  {
    std::cerr &lt;&lt; e.what() &lt;&lt; std::endl;
  }

  return 0;
}
</pre>
<p>
        See the <a class="link" href="tutdaytime2/src.html" title="Source listing for Daytime.2">full source listing</a>
      </p>
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        Return to the <a class="link" href="../tutorial.html" title="Tutorial">tutorial index</a>
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<p>
        Previous: <a class="link" href="tutdaytime1.html" title="Daytime.1 - A synchronous TCP daytime client">Daytime.1 - A synchronous
        TCP daytime client</a>
      </p>
<p>
        Next: <a class="link" href="tutdaytime3.html" title="Daytime.3 - An asynchronous TCP daytime server">Daytime.3 - An asynchronous
        TCP daytime server</a>
      </p>
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<td align="right"><div class="copyright-footer">Copyright © 2003-2021 Christopher
      M. Kohlhoff<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
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